The term “undertaking”, as used in this chapter, unless a different meaning clearly appears from the context:

1. Means    systems,    plants,    works,    instrumentalities,    and    properties    used    in revenue-producing undertakings, or any combination of two or more of such undertakings, which are used or useful in connection with:

a. The obtaining of a water supply and the conservation, treatment, distribution, and disposal of water for public and private uses; b. The collection, treatment, and disposal of sewage, waste, and storm water; c.    The generation, production, transmission, and distribution of natural, artificial, or mixed gas, or electric energy, for lighting, heating, and power for public and private uses; d. The operation of parking lots, trailer courts, and facilities for motor vehicles and house trailers; e. The purchase, acquisition, or establishment, maintenance, and operation of a public transportation system; f.    The purchase, acquisition, construction, establishment, maintenance, and operation of an airport and the facilities and services in connection therewith; and

g. The purchase, acquisition, construction, maintenance, and operation of a hospital; and

2. Includes all parts of any such undertaking and all appurtenances to the undertakings, including lands, easements, rights in land, water rights, contract rights, franchises, approaches, dams, reservoirs, generating stations, sewage disposal    plants, intercepting sewers, trunk connections, other sewer and water mains, filtration works, pumping stations, and equipment, and facilities in and upon such buildings and lands.